a CD ?
hell, I ain't using mine much these days
even tho it actually does sound very good
my Apple TV tho does sound much better on analoge out, through my 'old' source selector/preamp
obviously my TV screen digital/analoge converter aint much good
difference is like going from a mechanical device to good vinyl
so, yeah, even if the future may be a digital/analoge converter preamp, an old style full functional preamp can still be very usefull
at least to those who don't care much about surround receivers
hell, I ain't using mine much these days
even tho it actually does sound very good
my Apple TV tho does sound much better on analoge out, through my 'old' source selector/preamp
obviously my TV screen digital/analoge converter aint much good
difference is like going from a mechanical device to good vinyl
so, yeah, even if the future may be a digital/analoge converter preamp, an old style full functional preamp can still be very usefull
at least to those who don't care much about surround receivers
If you know how to, it is possible.
But knowing nothing about the sources you want to switch between, this would be suicide for your speakers.
The preamp is a true DC amp, so if you modify it to your wishes, be prepared ta catch your bass cones before they fly out your windows
....... be prepared ta catch your bass cones before they fly out your windows
sure hope noone would switch source input at high SPL
I would say not likely to happen
besides, it is to avoid exactly that
right now I have that feature on my present amp
exstremely nice, with multiple and different sources
but I guess you only build such a thing if you think it makes sense, and needs it yourself
There is no secrets at all.
Mail me, and you´ll have schematics for what ever reason for private use.
The gain is 6 dB, the frequency range is DC to 4MHz.
And just believe me, it is from DC.
The servo will deal alone with temp. drift.
And I guess you are using the digital volume control in the CD-player then.... OMG, why didn't we think of that
Hi Guys,
I am really surprised at your attitude but think of it. There are a few people at DIY that are really knowledgeable and could even point to a few matters of interest or of concern and if you were open and want to debate you may have had more genuine interest in your project.
You are saying, that you will build me a house, but I cannot see the plan, and you are the only person that knows it. I must accept that you are a master builder, but I see you work in insurance. My opinion would be, thank you, I will build my own house, at least I will not waste my money and I will know exactly what I get.
You talk about many things that you do not understand and you cannot even provide a basic specification, which is the place that a design begins. You say your amp really runs down to DC, well all amps can, that is nothing new nor is it special. A voltage regulator is an amp that operates on DC, yes really.
Why would you need a gain with 6dB and why 4 MHz, what is the benefit to run into the RF spectrum, what is the input impedance and output impedance, how does it perform with two tones, what is the distortion power distribution, etc.
I never said that I will never build it, if it has merrit and better designed than my own creations I would build it but I see nothing - a PCB layout not even a very good one for that matter as you are too afraid to provide some measured characteristics.
I am sorry guys you have been the victums of your own cleverness and probably landed you in a situation that few on this forum will pay much attention to you in future simply because I think you are lying, this pre-amp is most probably cut and paste from some circuits, and auto routed on a PCB with little or no knowledge of what is happening - hence my question of using transistors that operate in the GHz and offer 20mA Ic max.
You made it, heard that it works, (good or bad) and are ecstatic because you have had nothing better to compare it with so unfortunately throwing a 100 plus components at a 6dB gain is firstly ludicrous.
Have fun guys, you are not at all convincing, selling insurance and selling audio concepts to the converted is two very different things.
Kind regards
Nico
I am really surprised at your attitude but think of it. There are a few people at DIY that are really knowledgeable and could even point to a few matters of interest or of concern and if you were open and want to debate you may have had more genuine interest in your project.
You are saying, that you will build me a house, but I cannot see the plan, and you are the only person that knows it. I must accept that you are a master builder, but I see you work in insurance. My opinion would be, thank you, I will build my own house, at least I will not waste my money and I will know exactly what I get.
You talk about many things that you do not understand and you cannot even provide a basic specification, which is the place that a design begins. You say your amp really runs down to DC, well all amps can, that is nothing new nor is it special. A voltage regulator is an amp that operates on DC, yes really.
Why would you need a gain with 6dB and why 4 MHz, what is the benefit to run into the RF spectrum, what is the input impedance and output impedance, how does it perform with two tones, what is the distortion power distribution, etc.
I never said that I will never build it, if it has merrit and better designed than my own creations I would build it but I see nothing - a PCB layout not even a very good one for that matter as you are too afraid to provide some measured characteristics.
I am sorry guys you have been the victums of your own cleverness and probably landed you in a situation that few on this forum will pay much attention to you in future simply because I think you are lying, this pre-amp is most probably cut and paste from some circuits, and auto routed on a PCB with little or no knowledge of what is happening - hence my question of using transistors that operate in the GHz and offer 20mA Ic max.
You made it, heard that it works, (good or bad) and are ecstatic because you have had nothing better to compare it with so unfortunately throwing a 100 plus components at a 6dB gain is firstly ludicrous.
Have fun guys, you are not at all convincing, selling insurance and selling audio concepts to the converted is two very different things.
Kind regards
Nico
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And I guess you are using the digital volume control in the CD-player then.... OMG, why didn't we think of that
How did you guess Wadia has a built in 100 dB attenuator, a 15 ohm output impedance and a selectable output voltage for matching. Not the best but I would hate to hang anything on the end of it that is totally undefined.
I think you guys will do much better at selling esoteric speaker cables.
I've removed some rules-breaking posts. Cease and desist or the thread will be closed.I guess you find it pretty hard to buy a car... Or maybe you get the complete production-data from the dealer
About using the RF transistors:
BFR92 and BFT92 are used in our shunt regulator, but NOT as the power device. They are used in the gain-stage, to ensure gain at high frequency. The power device in the shunt is rated at 8Amps!
The output device in the line stage is rated at 150mA, which should be sufficient.
About the layout:
I don't know your background in PCB layout.... I have been doing layouts for about 14 years now. I have been doing as part of my job as an electronics R&D engineer, and also as a consultant. Both in the audio-industry, but also for more demanding industrial application, with extreme legal requirements and extreme lifetim expectations.... And I NEVER use autorouters....
As much as you really really would like it, I guess you will have quite a hard time finding anything really really bad about the circuit we are using or the actual implementation...
Even if I provide you the schematics, you will not build it anyway... You will just continue your attemt to find something bad about the schematic.
This is NOT our goal.... We spend years to achieve the best sonic performance. If you are more into dissect schematics, you really should find a different project, since this will not be of your interest.
As a direct consequence, I feel absolute no need to provide you the schematics.... And no matter how many posts you will make, this will not change.
Are you using an internal digital volume control?
Almost anything will do better not using a device like that. Even the latest and most noise and distortion free types, does have very negative influence on sound quality.
The only thing they do better is tracking, and they also are very cheap.
That is the main reason for building a preamplifier with an old style volume control. We did think of a motorized one, but could not find anything suitable. Hence the Alps, or by choice you can use P&G @20 times the price of the Alps.
But if you really do not these things, this project is much much to complicated to enter.
You can ask this same question about almost any preamp. In most domestic situations with short cable runs and reasonable power amp loads active preamps appear pointless. Yet, in mine and others' experience this is not the case, especially with digital sources. Not sure at all what is going on and no, it isn't simply the addition of noise and distortion which "improves" the sound, but i tend to look at (high quality) preamps as very subtle sound effect boxes. If all preamps were doing was amplify the sound, who would spend big bucks on high end units and why?
the above was cut short due to forum issues. what i wenty on to say is, the latest range of dac chips, not only from ESS, but also from akm and crystal semi all have integral very high bit depth digital volume control. I have heard people say they impact negatively, but imo this can only be either crazy talk, or prejudice. These chips all use higher than audio bandwidth and bitdepth to basically use the same mechanism that is used to create a soft or loud sample to control volume, to say these have a very noticeable negative effect is nuts, as it is indistinguishable from music that changes volume
some of the new range of usb->i2s converters also have such controls at the data level, one i'm using at the moment is 64bit, now these are basically perfect volume controls for digital source, to use anything else imo can only be for means of coloration.
some of the new range of usb->i2s converters also have such controls at the data level, one i'm using at the moment is 64bit, now these are basically perfect volume controls for digital source, to use anything else imo can only be for means of coloration.
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@ qusp:
Yeap... but the problem about using the internal digital volume control, however, is very easy to hear....
Be aware, that a 24bit DAc is NOT linear at the least significant bits. This means, that if you use these as a volume control, performance is de-graded.
Also be aware, that typically the noise-floor is NOT lowered, when using the internal volumecontrol. This means, that at -40dB volume, the noise is 40dB worse than at 0dB volume....
But again... If you cannot hear that, the DAC isn't the biggest performance issue in the setup....
Yeap... but the problem about using the internal digital volume control, however, is very easy to hear....
Be aware, that a 24bit DAc is NOT linear at the least significant bits. This means, that if you use these as a volume control, performance is de-graded.
Also be aware, that typically the noise-floor is NOT lowered, when using the internal volumecontrol. This means, that at -40dB volume, the noise is 40dB worse than at 0dB volume....
But again... If you cannot hear that, the DAC isn't the biggest performance issue in the setup....
I think you missed the point; it uses 48 bits and the other control in the i2s convertor i'm using is 64bit, the 24 used bits are untouched unless you use a silly amount of attenuation; far more than any sane person would set their system up for. i know you have magic ears and all, but myself and none of the other people that i know who have converted from using very high quality steppers hear this very obvious problem you speak of, because its not there.
now sure, if you want to add an entire circuit and a handful of components into the signal path to solve a 'transparency problem' go right ahead.
there are digital volume controls and digital volume controls, some of them cause the problem you mention, some do not unless you use them in a manner that is outside what is reasonable, besides, the thing that gets me about this argument that is often conveniently forgotten, is attenuating in the analogue domain causes loss of information, DNR and adds noise that is right there in the middle of the audio
just because its analogue does not mean its immune to information loss and noise, far from it....
now sure, if you want to add an entire circuit and a handful of components into the signal path to solve a 'transparency problem' go right ahead.
there are digital volume controls and digital volume controls, some of them cause the problem you mention, some do not unless you use them in a manner that is outside what is reasonable, besides, the thing that gets me about this argument that is often conveniently forgotten, is attenuating in the analogue domain causes loss of information, DNR and adds noise that is right there in the middle of the audio
just because its analogue does not mean its immune to information loss and noise, far from it....
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You tempt me. I haven't looked but from what I read you have published a layout and a BOM. How long do you imagine it will take me to write a netlist and generate a schematic?
Already you try our patience with a design that 'sounds good' but you publish no performance figures.
Maybe you would be better to set yourselves up as gurus if you can so readily find people to trust you with their time, energy and money.
Hare Krishnaaa...
Publish the schematic and have done with it.
I also work as an audio reviewer, which gives me the opportunity to put my hands on lots of nice gear.
Very lately I had a Nice DAC with a digital volume control.
The sound was absolutely best bypassing that volume control.
Also TI produces a very nice digital volume control, but its output is an op-amp. And it sounds as if was just so.
We also considered using relays i.e. 8 bit resolution, but we could in fact not find any relays, that was transparent.
That just about leaves us where we are.
But if you do not need a preamp, then it makes no sense to build one. And those who do need one, can build this and have a lot of fun.
The feedback from the guys who build it already, says that its transparancy is unsurpassed. Some people tok out their +10.000$ preamps, to use this one instead. That was our goal right from the beginning.
These guys could never dream of not using a good and strong preamplifier, neither could I.
I don´t know how fast you are, but I think it would be even faster if you mailed me
What kind of performance figures do you want?
THD+N is very low.
Actually so low, that we just stopped worrying about it.
The N component can´t even be detected by ear, when volume is turned up and down.
But not as low as op-amps can do.
Z out is 100 Ohms
Z in 20K Ohms
It is a fully discrete circuit with no NFB.
It has no capacitors in signalpath.
DC servos with a frequency as low as 1/60 Hz.
Push pull output stage.
2 stage regulated PSU with lightening fast shunt regulators without decoupling caps.
Z out from the shunts is just a few milliOhms from DC to around 10MHz.
And best of all, people have gone crazy about it.
And apparently there is no need for schematics, more than thousand people downloaded the building instructions, and I had mail and PM´s from a lot of lads from in here, who want to build it.
So there will be no schematic published just forget about it.
We want people to build it as it is, it is a closed project.
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